Megabot is a much larger robot so its construction
takes a more robust approach.

Step 1

The Megabot has a round base that is 22. 5” in
diameter. You will need to use a thicker material for its
construction. In my case, I used 1/2” birch plywood. To
make the base, I used a homemade compass fashioned
from a dowel, pencil, and nail. You can also use a piece
of string, nail, and pencil. Just make sure the nail is 11. 25”
from the point of the pencil.

Place the nail in the center of the board and mark out
the diameter of the base. You can use a scroll saw, band
saw, or jig saw to cut it out as shown in Figure 15. If you
have no way to cut the board, you can always use a square
base for your bot. This will work, but it will make it more
difficult to maneuver in tight places.

Step 2

To mount the wheels on the base, we’ll use a 4” x 14”
x 3/4” piece of wood to create a wheel sub-assembly. You
need to cut a 1-3/4” x 4-3/4” notch out of two ends of the
board as shown in Figure 16. These notches are used to
make space for the tires in our wheel assemblies.

Next, take an extra OF-64S actuator mount and
mark four holes as shown in Figure 17. Then, drill a
11/64” hole all the way through the boards at each of
the marks. You will need to make two of these wheel
sub-assemblies.

Step 3

Lay the boards out so that the cutouts are oriented as
shown in Figure 17 and drill a 1/2” hole 3/8” deep into
each of the holes.

Step 4

Now, take a wheel assembly and insert the four bolts
into the four holes as shown in Figure 18.

Note that you are inserting into the side of the board
without the counter-sunk holes that you created in Step 3.